JP3654610B2 - Electrophotographic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic apparatus that records on paper using an electrophotographic system such as a copying machine, a printer, and a facsimile.
[0002]
[Prior art]
An electrophotographic apparatus such as a copying machine, such as a color image recording apparatus, has a plurality of photoconductors and transfer paper transport belts that sequentially move in contact with the photoconductors, and are different from each other formed on each photoconductor. The color toner image is superimposed and transferred onto the transfer paper transported in contact with the transfer position of each photosensitive drum by the transfer paper transport belt, and after transfer, the transfer paper is separated from the transfer paper transport belt and fixed. Thus, an apparatus for recording an image includes a device for cleaning residual toner on each photoconductor. In this type of cleaning device, toner cleaned from the peripheral surface of each photosensitive drum by a cleaning member such as a cleaning blade or a brush roller provided in the interior of the cleaning device is provided in the width direction at the bottom of the device (coil screw). The toner is discharged from one end of the apparatus bottom, and the toner is transferred to a collected toner storage section provided separately from the cleaning apparatus.
[0003]
Techniques relating to this collected toner transfer (conveyance) device include the following. That is,
(1) The recovered toner discharge portion of the cleaning device and the recovered toner storage means provided separately from the cleaning device are connected by a pipe, and the recovered toner is transferred to the recovery storage means by a coil screw provided inside the pipe. (Conveying) technology,
(2) A technique in which the collected toner storage means is disposed near the collected toner discharge portion of the cleaning device and is transferred (conveyed) to the collected toner storage means mainly by gravity.
(3) A collected toner discharge portion of a plurality of cleaning devices and a collected toner storage means provided separately from the cleaning device are connected by a pipe, and the collected toner is collected by gravity or a coil screw provided inside the pipe. Technology to transfer (carry) to storage means,
There is.
[0004]
[Problems to be solved by the invention]
By the way, if the toner discharged from the above-described cleaning device is stored in a collection tank provided separately for each photoconductor, the required space in the machine becomes large, and toner scattering from each tank increases and the inside of the machine is easily contaminated. In addition, there are disadvantages such as taking time for maintenance. Therefore, each cleaning device leads to a common toner conveyance pipe through a branch pipe, and is collected by a conveyance screw extended in the common toner conveyance pipe into a single toner collection device connected to the common toner conveyance pipe. Something like this has been proposed.
[0005]
In this case, since the common inner diameter of the toner conveying pipe and the diameter of the conveying screw are uniform from the upstream end to the end connected to the toner recovery pipe, the branch pipes from each cleaning device are connected. When the amount of toner to be transported through the common toner transport tube increases every time and the cross-sectional area of the transport tube and the transport capability of the transport screw cannot keep up with the amount of toner to be transported, toner transport There is a problem that toner clogging in the tube and breakage of the conveying screw occur. In addition, since the toner falls freely due to gravity or is transported by a transport screw, there is a restriction on the layout of the recovery path, which complicates the recovery path (branch pipe, toner transport pipe), and is caused by heat and transport that accumulates in the machine. There is a problem that toner clogging and conveyance screw breakage are likely to occur due to frictional heat generated.
[0006]
Therefore, the present invention provides a cleaning device for each of the plurality of photosensitive members, so that even if the conveyance path becomes complicated, toner clogging, conveyance screw breakage, toner conveyance uncertainty, internal equipment, and unit layout are free. It is an object of the present invention to provide an electrophotographic apparatus capable of improving the degree of assembly, improving assemblability, maintainability, and reducing costs.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the electrophotographic apparatus according to claim 1 of the present invention includes a plurality of photoconductors, a transfer device that contacts the photoconductors and sequentially transfers a toner image from the photoconductor onto the transfer paper, An electrophotographic apparatus having a cleaning device provided for each of the photoconductors for cleaning toner remaining on the photoconductor after transfer of the toner image, and a toner recovery device for recovering toner from each cleaning device to a toner recovery container. In each of the above, the toner recovery paths from the respective cleaning devices are provided independently, and each of the recovery paths from the toner discharge port of each of the cleaning devices to the single toner recovery container is recovered from each of the cleaning devices. the toner arranged Mono pump for toner recovery for air transport into the toner recovery container, the toner images on the plurality of photoconductor Superposition characterized many to Rukoto amount of air supplied to the higher cleaning device the Mono pump located downstream in the transfer to the order.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing the overall configuration of a color image recording apparatus to which the present invention is applied. The color image recording apparatus includes an original reading unit 1, an image processing unit 2 that electrically processes a color separation image information signal output as a digital signal from the original reading unit 1, and an output from the image processing unit 2. The printer unit 3 forms a color image on a transfer sheet based on image information signals to be developed with yellow, magenta, cyan, and black (hereinafter abbreviated as Y, M, C, and Bk) toners.
[0011]
The document reading unit 1 is a scanning composed of a white light 5 for verifying scanning of a document on the document placing table 4, and mirrors 6, 7, 8 and a lens 9 for guiding reflected light from the document surface illuminated by the slit to the reading unit. An optical system and a dichroic prism 10 that separates colors into three primary colors of blue, green, and red, and a reading unit that includes three CCDs 11B, 11G, and 11R that receive and read the original image light that has been separated into light beams of three colors. . The image information of the three colors read by the three CCDs 11 is output as a digital signal, converted into an image information signal to be developed with Y, M, C, and BK toners by the image processing unit 2 and output to the printer unit 3. Is done.
[0012]
The printer unit 3 includes four photosensitive drums 14 on which toner images of four colors Y, M, C, and BK are formed (subscripts Y, M, C, and BK are added to elements to be described below). Are attached to the same level in parallel, and the four image information signals output from the image processing unit 2 are four. The laser light emitted from the laser light emitting device 12 is modulated in accordance with the signal, is incident on each of the four photosensitive drums 14 via the polarization means, is optically scanned, and an image is written on the photosensitive drum 14. . Around each photosensitive drum 14, similarly to a general electrophotographic recording apparatus, a charging charger 15, the writing position, the developing device 16, a transfer charger 17, and a cleaning device 24 are provided in the order of rotation. These components constitute each color recording device 13. Images written on the respective photosensitive drums 14 by laser light are developed by the developing device 16 to form toner images of Y, M, C, and BK.
[0013]
The transfer paper transport belt 21 is driven by the driven rollers 25a and 25b and the driving roller so that the upper running portion passes between the four photosensitive drums 14 and the transfer charger 17 provided below the four photosensitive drums 14. 26 is provided. The transfer paper delivered from the paper supply unit 19 by the paper supply roller 18 is supplied to the transfer paper transport belt 21 by the registration roller 20 at the timing when the image on the photosensitive member and the leading edge are aligned. The transfer paper is conveyed by the transfer paper conveyance belt 21 in contact with each photoconductor drum 14 at the transfer position. Under the action of the transfer charger 17, the four color toner images BK, C, M, and Y are transferred onto the transfer paper. The transfer paper is separated from the transfer paper transport belt 21 and fixed by the fixing device 22 to form a color image corresponding to the original. Discharged.
[0014]
FIG. 2 is a view showing a cross section of the cleaning device 24 for the photosensitive drum 14, in which the photosensitive member 14 extends substantially over the entire length in the casing 24 a extending in the width direction of the photosensitive drum 14 over the entire length. A brush roller 24b in contact with the outer peripheral surface of the drum 14 and a cleaning blade 24c whose base is fixed to the casing 24a and whose tip is pressed against the outer peripheral surface of the photosensitive drum 14 are provided. The cleaned residual toner collects at the bottom of the casing 24a, and is discharged from one side of the casing 24a by the conveying screw 24d extending in the width direction at the bottom of the casing 24a. The transfer paper transport belt cleaning device 27 has the same configuration.
[0015]
Next, FIGS. 3 and 4 show the configuration of the toner conveying device from the toner discharge ports of the cleaning devices 24Y, 24M, 24C, and 24BK attached to the respective photosensitive drums 14 to the single toner recovery tank 28. FIG. FIG. However, since the toner conveying device has the same configuration in the cleaning devices for each color, only the Y toner device is shown and described as a representative. However, subscripts are omitted in the description.
[0016]
The toner collected by the cleaning device 24 is transferred to a toner guide member 30 engaged with the toner from a collected toner discharge portion 29 provided at an end of the casing 24a of the cleaning device. The toner guide member 30 serves as a toner transfer path for sending toner from the cleaning device 24 to the screw pump for collecting toner , specifically, to the Mono pump 31 .
[0017]
Mono pump 31, the holder 32, the interior of the rotor 33 thereof, constituted by a stator 34 made of an elastic material as rubber material or the like which is secured in a holder 32 so as to surround the rotor 33. The rotor 33 is connected to the conveying screw 36 in the case 35 of the toner guide member 30. The end of the case 35 of the toner guide member 30 is sealed with a seal member 37, and a bearing 38 and a driven gear 39 are attached to the end of the conveying screw 36.
[0018]
The Mono pump 31 attached to the case 35 of the toner guide member 30, the support member 40 of the case 35 of the toner guide member 30, the driving motor 41 of the variable rotational speed is mounted, the driving gear 42 of the driving shaft end The end of the conveying screw 36 is meshed with a driven gear 39.
[0019]
Between the inner face of the side face the holder 32 of the stator 34 of the Mono pump 31 described above there is a gap of about 1 mm, the gap is connected to the collected toner passage 43, also blowing air into the recovery toner passage 43 through the gap An air supply port 44 is provided. The air supply port 44 communicates with an air pump 45 having a variable air flow rate via an air discharge port 46 and a pipe 47. The air pump 45 blows air into the collected toner passage 43 through the air supply port 44 at a blowing rate of about 0.5 to 1 liter / minute. Thus, increases the flowability of the collected toner in the Mono pump 31, the collected toner transfer at the Mono pump 31 is ensured. Toner which has passed through the Mono pump 31 is sent to recovery tank 28 via the recovery toner transfer pipe 48. The recovered toner transfer pipe 48 may be made of a flexible material having excellent toner resistance (for example, soft vinyl chloride, nylon, Teflon (registered trademark) ).
[0020]
Note operation of the above-described recovery toner transfer device may be driven at almost the same timing as the cleaning device 24, but the control of the drive motor 41 and the air pump 45 of the Mono pump 31 when stopped and during operation the start of the cleaning device 24, At the start of operation of the cleaning device 24, only the air pump 45 is turned on. After 0.5 to 1 second, the drive motor 41 is turned on. When the cleaning device 24 is stopped, the drive motor 41 is turned off and then only the air pump 45 is turned on for 1 to 3 seconds. It is better to control the system so that it operates. This makes it possible to prevent clogging of collected toner and to ensure toner transfer.
[0021]
By the way, the amount of toner discharged from each cleaning device 24 is different, but this is due to superposition transfer. If there is a toner image already transferred on the photosensitive drum 14 on the transfer paper in the transfer process, the toner is transferred. This is because reverse transfer is performed to the photosensitive drum 14 in the next process. That is, when the toner images on the plurality of photosensitive drums 14 are superimposed and transferred, the amount of collected toner increases as the cleaning device 24 is located downstream in the transfer order. Contrast can not follow the toner conveying ability of the Mono pump 31 on the downstream side, it is considered that the toner is packed in Mono pump 31 or in the toner transport path on the upstream side. It may advance using a large Mono pump 31 capacity to a margin, but less preferred in terms of layout. The rotational speed of the rotor 33 of Mono pump 31 is only a low rotation can, it is desirable to prevent the fluidity deterioration of the toner by suppressing the stress (pressure, heat) to the toner. Furthermore, increasing the bulk density by feeding air to the toner Mono pump 31 Upon conveys the toner, while increasing the fluidity of the toner, which is also different quantity of air necessary in the toner to be conveyed, the required amount is obtained Otherwise, not only the transportability is deteriorated but also stress (pressure and heat) is applied to the toner, and the transportability is further deteriorated to cause toner clogging.
[0022]
Right side of FIG. 5, the horizontal axis the rotational speed of the rotor 33 of the Mono pump 31 is a graph showing the amount of toner relationship can be transported and the rotation speed. As can be seen from this graph, the conveyance amount increases with the rotation speed. In other words, the recovered toner or toner amount that can be carried in a certain rotational speed, if sent into the Mono pump 31, the toner is not conveyed, the toner agglomeration, the toner clogging, further cause damage to the pump or motor. Further, the left side of FIG. 5 is a graph showing the relationship between the toner amount and the amount of air necessary for conveyance, with the amount of toner conveyed on the vertical axis. As can be seen from this graph, the required amount of air to be supplied increases as the transport amount increases. If the necessary amount of air is not obtained, the bulk density of the toner to be conveyed is lowered, and the fluidity of the toner is lowered. When the toner in this state is pushed out by the rotor, the transportability is deteriorated, stress (pressure, heat) is applied to the toner, toner lump (aggregation) occurs, the toner is clogged, and further, the pump and the motor are damaged.
[0023]
Therefore, in the embodiment of the present invention, as well as increase the amount of air supplied to the cleaning device 24 as the Mono pump 31 located downstream in the transfer order superposition of toner images, and many rotation speed of the Mono pump 31. The rotational speed N1, N2, N3, N4 in FIG. 5 as the rotation speed of the Mono pump 31 located from the upstream side in the transfer-sheet conveying order, the amount of air required for their toner conveyance amount L1, L2, L3, L4 Similar the amount of air supplied to the Mono pump 31 located upstream in the transfer-sheet conveying order in, and large as respectively downstream.
[0024]
【The invention's effect】
As described above, the electrophotographic apparatus according to claim 1 is provided for each of the plurality of photoconductors, and the toner recovery path from the cleaning device to the toner recovery container is provided independently, and the toner recovery path is provided for each recovery path. since in such a manner that by arranging the Mono pump, even toner recovery route is complicated, clogging the toner due to heat or the like, there is no damage to the conveying screw, can transport reliable recovery toner, also constitutes a device Machine elements, unit layout flexibility, ease of assembly, maintainability, and cost reduction, and even if the amount of toner collected and transported downstream increases in the transfer order, toner transport is ensured there is an effect that ing to allow.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the overall configuration of a color image recording apparatus to which the present invention is applied.
FIG. 2 is a cross-sectional view of a photosensitive drum cleaning device.
FIG. 3 is a perspective view illustrating a configuration of a toner conveying device from a toner discharge port of a cleaning device attached to a photosensitive drum to a single toner recovery tank.
FIG. 4 is a sectional view of the same.
FIG. 5 is a graph showing the relationship between the required air amount and rotor rotation speed and the toner conveyance amount in the cleaning device of the embodiment of the invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Original reading part 2 Image processing part 3 Printer part 4 Original mounting stand 12 Laser beam emission apparatus 13 Color recording apparatus 14 Photosensitive drum 15 Charger charger 16 Developing apparatus 17 Transfer charger 18 Paper feed roller 19 Paper feed part 20 Registration roller 21 Transfer sheet conveying belt 22 fixing device 23 the sheet discharge roller 24 a cleaning device 27 transfer-sheet conveying belt cleaning device 28 recovery tank 29 collecting the toner discharge portion 30 the toner guide member 31 Mono pump
32 Holder 33 Rotor 34 Stator
35 Case 36 Conveying screw 37 Seal member 38 Bearing 39 Driven gear 40 Support member 41 Drive motor
42 Drive gear 43 Collected toner passage
44 Air supply port 45 Air pump 46 Air discharge port 47 Pipe 48 Collected toner transfer pipe

Claims (1)

A plurality of photoconductors, a transfer device that sequentially contacts the photoconductors and transfers a toner image from the photoconductor onto the transfer paper, and a toner that is provided for each of the photoconductors and remains after the toner image is transferred onto the photoconductors In the electrophotographic apparatus having a cleaning device for cleaning the toner and a toner recovery device for recovering the toner from each cleaning device to a toner recovery container, a toner recovery path from each of the cleaning devices is provided independently. For each collection path from the discharge port to a single toner collection container, a toner collection mono pump for conveying the toner collected from each cleaning device to the toner collection container by air is arranged . The more the cleaning device located on the downstream side in the order in which the toner images on the photoconductor are superimposed and transferred, the above mode. Electrophotographic apparatus, wherein a number to Rukoto amount of air supplied to the Noponpu.

Images